This invention relates to orthopedic casting materials and protective pads.
Many different articles have been developed for use as orthopedic casting materials in the immobilization of broken or otherwise injured body limbs and for use as protective pads to protect against impact injuries while participating in a physical activity such as an athletic event. Some of the first casting materials developed for this purpose involved the use of plaster of Paris bandages consisting of a cotton gauze mesh fabric with plaster incorporated into the openings and onto the surface of the mesh fabric. Plaster of Paris casts, however, have a number of attendant disadvantages, including a low strength-to-weight ratio, resulting in a finished cast which is very heavy and bulky. In addition, plaster of Paris casts develop their strength over a relatively long period of time, thus making it necessary to avoid weight bearing situations for up to 24 to 48 hours. Furthermore, plaster of Paris casts typically disintegrate in water, thus making it necessary to avoid bathing, showering, or other activities involving contact with water.
A significant advancement in the art was achieved when synthetic polyisocyanate prepolymers were found to be useful in formulating a resin for orthopedic casting materials and for preparation of protective pads. Typical commercially available synthetic orthopedic casting materials comprise a knit fiberglass fabric backing impregnated with a polyisocyanate prepolymer resin. These orthopedic casting materials can provide significant advancement over the plaster of Paris casts, including a higher strength-to-weight ratio. However, knitted fiberglass backings of conventional casting articles or protective pads may become quite rough when cured and often produce casts or protective pads with sharp edges. The sharp edges can cause skin abrasions, skin irritation and/or snag clothing. As a result, the health care worker or athletic event participant has had to employ padding materials at the edges to attempt to avoid contact of the casting article or protective pad with the skin.
From the foregoing, it will be appreciated that what is needed in the art is an orthopedic casting material which has the benefits of synthetic orthopedic casting materials, e.g., high strength-to-weight ratio, but without the sharp edges. Such orthopedic casting materials and methods for preparing the same are disclosed and claimed herein.
In general, the orthopedic casting tapes of the present invention comprise a first longitudinally extending region of a soft casting material and a second longitudinally extending region of a hard casting material that is connected to the first region. The soft and hard casting materials may comprise, for example, soft or hard curable resins associated with a backing, soft or hard thermoplastic materials associated with a backing, or soft or hard extruded casting materials.
In one preferred embodiment, the present invention provides orthopedic casting tapes comprising a backing and at least one curable resin associated with the backing. The casting tape includes at least one longitudinally extending region of a soft casting material and at least one longitudinally extending region of a hard casting material. Preferably, the longitudinally extending region of soft casting material and the longitudinally extending region of hard casting material comprise different curable resins. Alternatively, they may comprise two different backings.
The casting tapes most preferably have one or two edge regions of the softer casting material. When wrapped about a limb, the soft edge regions may form a soft edge of the cast. For a typical 10 cm wide casting tape, the soft edge regions are preferably at least 0.5 cm wide.
The invention also describes novel methods of making orthopedic casts including the steps of: providing a curable casting tape having at least one longitudinally extending region of a soft casting material and at least one longitudinally extending region of a hard casting material; initiating the cure of the casting tape (e.g., by exposing the casting tape to water); optionally wrapping the casting tape so that the soft region overlaps at one or more edges of the cast; and allowing the casting tape to cure to form an orthopedic cast.
The invention also describes novel manufacturing methods for making these new orthopedic casting tapes. In one embodiment, these new methods include the steps of providing a fabric backing; and coating two different curable resins on the backing to form two adjacent longitudinally extending regions having differential hardness.
The present invention also provides improved splint articles comprising, e.g., a backing and at least one curable resin associated with the backing. In general, the splint article has a hard center region and at least one soft edge region. The splint may further comprise a thumb hole having a soft edge region surrounding the periphery of the thumb hole.
The present invention also provides improved protective padding articles comprising, e.g., a backing and at least one curable resin associated with the backing. In general, the protective pad article has a hard center region and at least one soft region. The protective pad can be custom-fitted to a portion of the human body for protection against impact injuries.
A xe2x80x9ccasting materialxe2x80x9d refers to a material (e.g., a composite material, a resin coated sheet, etc.) that undergoes a change of state from a generally moldable first state to a generally nonmoldable second state, thereby allowing the formation of a customizable support device. The support devices of the present invention are characterized as having at least one xe2x80x9csoft regionxe2x80x9d and at least one xe2x80x9chard region.xe2x80x9d The second states of the soft region and the hard region differ in at least one physical property, with the hard region being at least discernibly more rigid, less resilient or harder than the soft region. The term xe2x80x9cdifferential hardnessxe2x80x9d refers to the relative difference in rigidity, resilience, or hardness between the soft and hard regions of a casting tape or splint (i.e., the relative difference between the second states of the two regions).
A xe2x80x9cprotective padxe2x80x9d is a form of casting material that, while in the moldable first state, can be custom-fitted to a portion of the human body. After changing to the nonmoldable second state, the protective pad is secured to the human body for protection against impact injuries.
A xe2x80x9ccasting tapexe2x80x9d refers to an elongated strip of a casting material. The casting tapes of the present invention may be optionally wound on a roll prior to use and are characterized as having at least one longitudinally extending xe2x80x9csoft regionxe2x80x9d and at least one longitudinally extending xe2x80x9chard region.xe2x80x9d The second states of the soft region and the hard region differ in at least one physical property, with the hard region being at least discernibly more rigid, less resilient or harder than the soft region.
The xe2x80x9csoft regionxe2x80x9d of a casting material (e.g., casting tape, splint or protective pad) is that region of the casting material that comprises a soft casting material. A xe2x80x9csoft casting materialxe2x80x9d preferably refers to a casting material that undergoes a change of state from a generally moldable first state to a second state comprising a generally semi-rigid, resilient, or soft support device. A soft casting material includes a soft resin coated on a backing, as well as a soft extruded casting material. A xe2x80x9csoft resinxe2x80x9d preferably refers to a curable resin system that, when coated or otherwise applied onto a backing and cured, forms a generally semi-rigid, resilient, or soft support device. More preferably, the soft resin, when coated and cured onto the edge of a traditional fiberglass backing, provides an edge that doesn""t cut and/or abrade the wearer""s skin or otherwise hurt the wearer.
The xe2x80x9chard regionxe2x80x9d of a casting material (e.g., casting tape, splint or protective pad) is that region of the casting material that comprises a hard casting material. A xe2x80x9chard casting materialxe2x80x9d preferably refers to a casting material that undergoes a change of state from a generally moldable first state to a second state comprising a generally rigid, non-resilient, or hard support device. A hard casting material includes a hard resin coated on a backing, as well as a hard extruded casting material. A xe2x80x9chard resinxe2x80x9d preferably refers to a curable resin system that, when coated or otherwise applied onto a backing and cured, forms a generally rigid, non-resilient, or hard support device. More preferably, the hard resin, when coated and cured onto a traditional fiberglass backing, provides a rigid support device that can support the weight normally carried by the limb around which the support device is wrapped.
A xe2x80x9ccurable resin systemxe2x80x9d refers to any type of resin system that undergoes a change of state from a generally flowable or moldable uncured first state to a generally nonflowable or nonmoldable cured second state.
The terms xe2x80x9cbackingxe2x80x9d; xe2x80x9ccarrierxe2x80x9d; and xe2x80x9cscrimxe2x80x9d refer to the structure upon which one or more curable resins are coated or otherwise applied. A xe2x80x9cfabric backingxe2x80x9d is a backing that comprises a knit, woven or nonwoven fabric material.
The term xe2x80x9cassociated withxe2x80x9d refers to the intimate relationship between the resin system and the backing, such as may be accomplished, for example, by coating a backing with a resin and/or impregnating a backing with a resin.